PURPOSE: To enable to detect the generation of an abnormal condition of a tool easily and correctly, by a method wherein the current passing in a feed motor is detected when an abnormal condition occurs at a turning tool, and the condition is judged to be abnormal when the current value detected exceeds a preset value.
CONSTITUTION: A main spindle motor 2 of a swivelling automatic machine 1 rotates a chuck 3 gripping a work. The feed motor 4 controls the feed of a tool rest 6 fitted with cutting tools 7, 8 or the like. A setter 12 is provided for setting a threshold current and it generates a set voltage signal corresponding to the threshold current. A comparator 13 compares a signal V generated by a current detector 10 with the set signal Vc, and it generates an abnormality detection signal when V> Vc. Thus, a threshold value is selected from a plurality of threshold values in accordance with NC information, and an abnormality detection signal is outputted when the current flowing in the feed motor exceeds the relevant threshold value.
KASHIMOTO SEIGOU
SAKAMOTO CHIAKI
MIZUTANI EIJI
| JPS5537104U | 1980-03-10 | |||
| JPS50117481U | 1975-09-25 | |||
| JPS51122881A | 1976-10-27 | |||
| JPS4719480A |